The invention is concerned with a peritoneal dialysis device with a balancing arrangement with two chambers, each of which can be switched with a valve arrangement into a filling or emptying phase, with the peritoneal dialysis liquid source connected to the balancing arrangement through an inlet line, a catheter line that can be connected to the peritoneal catheter, starting from the balancing arrangement, a discharge line starting from the balancing arrangement, a pump arrangement for transporting fresh or used peritoneal dialysis fluid and a control unit for controlling the valve arrangement and the pump arrangement.
Devices for automated peritoneal dialysis, called "cycler" below, have the task to move peritoneal dialysis fluid in a defined amount and at a defined temperature into the peritoneal cavity of a patient with the aid of a permanent catheter and then to remove it again after a period of exposure, whereby the ultrafiltrate produced in the peritoneal cavity during the dialysis treatment is to be removed at the same time. This basic process is repeated at cyclic intervals corresponding to the particular clinical procedure and the individual requirements of the treatment.
The fluid should be administered in as short a time as possible in a predetermined amount and, after the exposure time, should be removed, again in as short a time as possible, whereby the amount removed must be determined more accurately so that a sufficiently accurate conclusion can be obtained about the balance and thus about the amount of ultrafiltrate produced by the body. During the inlet and outlet of the fluid, the patient must not be endangered and the way the patient feels must not be influenced adversely. It must also be determined accurately as to when the peritoneal cavity is sufficiently empty in order to start the next inlet.
Usually, the patient connects himself to such a cycler during at-home dialysis. The actual treatment then partially takes place during sleep, so that simple operation and absolute safety are indispensable. The function should not be influenced adversely by corpuscular components in the discharged fluid, which may occur, especially in the case of patients with inflammations. Finally, the fluid transfer must take place under absolutely sterile conditions because otherwise peritonitis may occur, which is sometimes life-threatening.
Already a number of peritoneal dialysis devices have become known, some of which are fully automatic, but fulfill the above requirements only partially.
A peritoneal dialysis device has become known from the Munchener Medizinischen Wochenzeitschrift (1972), p. 313, where a certain amount of peritoneal dialysis fluid by volume is administered to the patient. After the dialysis phase, this fluid is again removed from the patient and a volume balance must be set up. However, it is not obvious as to how the amount of ultrafiltration is to be determined.
An automatic peritoneal dialysis device has also become known from U.S. Pat. No. 3,709,222, which administers dialysis fluid to a patient with the aid of proportioning chambers in a time-dependent manner. Volumetric control of the transported fluid cannot be attained with this arrangement because the expandable chambers used there, for example, the backflow chambers, are used in connection with path-dependent sensors, so that accurate volumetric control is not provided.
Further peritoneal dialysis devices are described in U.S. Pat. No. 4,096,859, 4,412,917, 4,381,003, and 5,004,459. According to the first two US patents, weighing means are used which are difficult to handle and therefore do not come into consideration because the handling of the cycler must be as simple as possible. The devices according to the latter two US patents also have disadvantages, since these use peristaltic pumps, for which it is known that the transport rate depends on the inlet pressure. Since these inlet pressures vary greatly, depending on the type of transport, such pump arrangements have very large volumetric errors, so that one cannot use them in ultrafiltration control in peritoneal dialysis.
EP-A 149,001 describes a peritoneal dialysis device in which the dialysis fluid in an extracorporeal cycle is introduced into the patient through the semipermeable membrane of a filter through the catheter. Although this device operates partly controlled, partly regulated, it is too expensive and it is also difficult to operate, quite apart from the fact that the disposables used there are too expensive. The same applies to the disposable device known from DE-G 87 14 464.
Finally, exactly balancing systems are known for hemodialysis in which fresh and used dialysis fluids are constantly balanced against one another in a closed cycle in a balancing chamber.